HONOLULU (AP) — A Hawaii state lawmaker is pressing military officials for a formal investigation into the unexplained death of a 16-month-old boy who died while under care of his Marine father.

The Honolulu Star-Advertiser reported Friday that Rep. John Mizuno led a silent march outside the state Capitol on 30 with the boy's mother.

The boy died May 20 while under care of his father, 24-year-old former Marine Cpl. Christopher Bahm. The boy's mother, Jerlee Bahm, says the father was in the process of being kicked out of the Marines when the boy died.

Honolulu police investigated the death but the case stalled because the cause of death could not be determined with medical certainty.

Deputy Medical Examiner Masahiko Kobayashi labeled the death a "sudden unexplained death in childhood."